SpaceX set to try again for ISS Tuesday

SpaceX had its Falcon 9 rocket on the launch pad for an early Saturday, May 19 launch. All seemed to be going well as the five main engines on the rocket lit, only to be shut down almost immediately. The ignition sequence was canceled with the rocket engines aglow after a slightly high combustion chamber pressure was noted. This is the latest delay in what's becoming common in the attempt to be the first company to send a private spacecraft to the International Space Station.

SpaceX has announced that it will try to lift off again Tuesday. The cause of the slightly high-pressure in one of the rocket engines has been identified, and a faulty part has been replaced. The launch on Saturday was scrubbed less than a second before liftoff. The cause of high-pressure in one of the engines was determined to be a defective valve.

The valve was easy to reach, and has now been replaced. That particular part had been tested previously, and the tests raised no indication of defect. It's certainly better for the launch to have been aborted on the launch pad, rather than a faulty valve leading to a disaster such as an explosion during flight. SpaceX issued an official statement Saturday noting that the high-pressure was in engine five's combustion chamber.

Today SpaceX Exploration Technologies, (SpaceX) issued the following statement on today's launch attempt.

Today's launch was aborted when the flight computer detected slightly high pressure in the engine 5 combustion chamber. We have discovered root cause and repairs are underway.

During rigorous inspections of the engine, SpaceX engineers discovered a faulty check valve on the Merlin engine. We are now in the process of replacing the failed valve. Those repairs should be complete tonight. We will continue to review data on Sunday.

If things look good, we will be ready to attempt to launch on Tuesday, May 22nd at 3:44 AM Eastern.

[via WSJ]